Cellulose sheets and processes fob



E. CZAPEK Dec. 213, 1947.

GELLULOSE SHEETS AND PROCESSES FOR MAKING THEM I 2 Sheets-Sheet lOriginal Filed Aug. 12. 1937 INVENTOR EM/L cZAPE/f av ATTORNEY E. CZAPEKDec.- 23, 1947.

CELLULOSE SHEETS AND PROCESSES FORMAKI-NG THEM I 2 Sheets-Sheet 2Originl Filed Aug. 12, 193'? R O T N E V m f u. CZAZ av I ATTORNEYReissued Dec. 23, 1947 CELLULOSE SHEETS AND PROCESSES FOR MAKING THEMEmil Czapek, New York, N. Y.

Original No. 2,234,964, dated March 18, 1941,

Serial No. 158,746, August 12, 1937.

Application for reissue July 8, 1946, Serial No. 681,896

15 Claims.

This invention relates to the production of improved cellulose sheets,films or the like as new articles of manufacture, and the processes ofmaking the same.

Among the objects of the present invention, it is aimed to provide animproved cellulose sheet, film or the like of an exceedingly uniformphysical structure throughout having a practically equal tension andshrinkage characteristic in length as well as in width.

It is still another object of the present invention to provide animproved cellulose sheet, film or the like of an exceedingly slightthickness without striations and the like and having a width of fortyinches or more by means of a continuousl operating process.

It is still another object of the present invention to provide improvedprocesses for producing the aforesaid improved cellulose sheets, filmsand the like.

These and other features, capabilities and ad vantages of the presentinvention will appear from the subjoined detail description of thearticle, processes and machines for carrying out the processesillustrated in the accompanying drawings in which Figure 1 is a sideelevation more or less diagrammatically of one embodiment;

Figure 2 is a side elevation of the feeding device used in theembodiment of Fig. 1;

Figure 3 is a fragmental transverse section of the feeding device shownin Fig. 2;

Figure 4 is a side elevation more or less diagrammatically of anotherembodiment;

Figure 5 is a fragmental plan of the embodiment shown in Fig. 4; and

Figure 6 is a front elevation of one of the conveyor supporting idlersused in the embodiment of Fig. 4.

The present invention essentially uses a pouring base onto which acopper oxide ammonia cellulose solution is evenly poured by means of anexact fitting nozzle. Thereupon, the solution which adheres to the baseand therefore cannot be subjected to stretching or extending, passes bymoving or rotating at the base into a coagulation bath. In thecoagulation bath which is in continuous movement, the poured sheet willbe coagulated to a strip and only then removed when. the coagulation hasbeen completed and the solution of the coagulation bath has penetratedthe sheet to the pouring base. The film after re moval has practicallythe same length and width as the formerly spread solution andfurthermore 2 does not change these dimensions while passing through thebath.

To carry out the process in accordance with the invention, it isdesirable to use, not only the apparatus but also the concentration andchemical proportions in the cellulose solution, and the treating bathsnow to be mentioned.

In the embodiment shown in Fig. 1, there is provided a nozzle I forfeeding a solution of copper oxide ammonia cellulose onto a supportingbase consisting in the present instance of the supporting face 2 of thedrum 3, which, however,

also may consist of an endless band.

The drum 3 is ro-tatably mounted on the shaft 4 extending through thetrough 5, the arcuate wall 6 of which is spaced from the face 2 auniform distance throughout, while the end faces of the drum 3 arepreferably closed and in engagement with the plane end walls 1 of thetrough 5. The drum 3 is preferably provided with a metal cylindricalwall member to provide the supporting face 2, the wall being composed asan instance of either iron, steel, nickel or the like or the wallprovided with a coating of nickel, chromium or the like and then eitherhighly polished to form a gloss or glistening surface or else dullfinished or provided with a finish consisting of a graduation of one orthe other ac cording to the surface finish of the film, sheet or thelike to be produced.

The main copper oxide ammonia cellulose containing solution isintroduced by the nozzle I to the metallic surface 2 of the drum 3, thenozzle I having a long narrow discharge opening 8, the width of which isadjustable by the pivotally mounted wall member 9.

When enlarging or narrowing the discharge opening by shifting the wallpart 9, accbrdingly more or less cellulose solution will flow throughthe opening 8 onto the pouring base 2. The nozzle l itself is supportedin a bracket 12 which is pivotally connected to rotate about the pivotsl3, and is provided with the rollers 14 resting on the drum 3. Thenozzle l is adjustably mounted in the bracket 12 and rests on thepouring base 2 by means of the two rotating rollers I48. The position ofthe nozzle l is regulated through the screw H. In order to prevent anyvagrant discharges from the sides of the nozzle l for the severaladjustments possible, there are proyided the vertically adjustable endplates or baffles I 41 having vertically extending slots MB cooperatingwith the wing nuts I49.

Attached to the lower edge of the wall ll] of thenozzle l is a bar [5which has been tapered into a knife-like edge and by a set of screws IS-the position thereof may be adjusted. The adjustment must be to thefinest extent and very exact, as the thickness of the film is adjustedand regulated thereby,

The thickness of the finished .film is determined by, i. e.,proportionately to, the amount of cellulose solution 29 which theknife-like edge of the bar I leaves on the pouring base 2.

The width of the slot 8 will be adjusted through changing the wall 9 toinsure sufficient cellulose solution in front of the edge I5 so that thecellulose solution will be sufficiently spread out on the pouring base 2below the nozzle. The width of opening of the nozzle I depends upon thethickness of the film to be manufactured, on the velocity of the drum 3and on the viscosity of the cellulose solution.

The drum 3 rotates in the direction of the arrow II 6. The cellulosesolution is spread direotly onto the surface by rotating the drum 3without passing through a free intermediate space, and thereupon passes.into trough 5' and is here coagulated by the fluid contained therein.

The trough 5 will be supplied with a treating fluid introduced throughthe inlet H, the treating fluid consisting essentially of sodiumhydroxide, ammonia and copper, which is subsequently discharged throughthe outlet I8.

It will be noted that the inlet I! and outlet I8 are disposed at theupper level of the fluid in the trough 5 and at the opposite endsthereof, the inlet just below the position where the film I9 leaves thedrum 3 and the outlet I8 a short distance below where the solution 20 isinitially poured onto the outer face 2 of the drum 3.

The concentration and the velocity of the fluid flowing through trough 5is determined by the components of the interacting solutions and fluids,hereinafter set forth in detail.

The film layer I9 will adhere. to the surface 2. of the drum 3 by itsuncoagulated surface during the entire coagulation process and does notpermit that any part of the fluid in trough 5 penetrates between theface 2 and the adhering surface of the layer I9. This coagulationproceeds progressively through the film from the exposed surface to theunderlying adhering surface. Only after the coagulation has beencompleted, will the coagulation fluid penetrate through the coagulatedlayer I9 and thereby arrive at the surface 2 of the drum 3 which it nowwets. Furthermore, only after this has been accomplished will the sheetI9 be taken from the drum 3..

For a proper coagulation of layer I9, it is important that thecoagulation fluid in trough 5 flows past the layer I9. In order toeffect agood flow or movement. of the fluid, trough 5 is so shaped thatonly a small space intervenes between the pouring face 2 and theopposite wall of the trough 5' in the entire extent through which thecoagulation fluid flows. Velocities of two-inches per second and abovefor the movement of the fluid are preferred,

The thus produced sheet or strip l9 may be removed from the surface 2without difllculty. It is completley coagulated and still of the samelength. and width as at the beginning of the proc-- .ess. The strip I 9passes now for ashort time through another trough containing. acoagulation fluid, in order to wet that surface of the sheet which hadnot been touched, by the coagulation bath so long as it remained on: thebase 2.

After the layer I9 leavesv the bath in the trough 5' and while still inadhesive engagement with the face 2 of the drum 3 until the face 2entitrely clears the upper level of the bath, the layer I9 then passesonto the outer surface of the roller 2| from which it passes into thecontainer 22 so that the face of the layer heretofore in engagement withthe face 2 of the drum 3 may now be effectively treated with acoagulation fluid similar to that contained in the trough 5.

In order to effectively dry the surface 2 and thereby remove anydeposits, moisture and the like either from the strip I9 or from thetrough 5 after the strip passes onto the roller 2| and in the area ofthe surface 2 disposed between the roller 2| and the nozzle I, there areprovided scraping means, such as the scrapers I 42 and I43 consisting inthe present instance of the blades pivotally mounted on the shafts I44and I45 so that as here shown they rest by gravity on the surface 2 andin opposition to the direction of movement of such surface 2.

After leaving the roller 2| and in order to facilitate guiding the stripl9 through the bath 23 in the container 22, the strip next passes downunder the roller 24 near the lower end of the container 22, then upabove the roller 25 before being passed into the water 28 in the nextcontainer 29 where any of the bath fluid adhering to the outer faces ofthe strip I9 is now effectively washed off and some of the coagulationbath fluid which has generated the strip or been difiused into the samewill be diluted and removed in part. after leaving the roller 25 firstpasses around the roller 39 adjacent the lower end of the tank 29, thenaround the upper roller 3|, again down around the lower roller 32, againup and around the upper roller 33, again down and around the roller 34and then up out of the tank 29 around the roller 35 before beingintroduced into the acid bath 35 contained in the tank 31.

The strip I9 will be. guided into and out of the acid bath 36 by meansof the rollers 38 to 43 inclusive, in the manner well known in the art,where the strip I9 will be regenerated and the copper effectivelyremoved.

After the strip I9 has been completely freed of the copper, it is nowpassed through several baths of clean, clear water and impregnated withsofteners or plasticizers and dried. For drying the strip I9, the sameis passed either through a well-known drying cylinder, not shown, orsubjected to a stream of warm air supplied by a suitable blower or thestrip subjected to a combination of both such drying treatments.

Preferably, in the embodiment just described, as shown in Fig. 1, theinlet 44 is connected to an extended tubular spray I50 having aplurality of branches extending adjacent to the path of movement of thestrip I9 and provided with discharge openings directed at the face ofthe strip I9;

In. the. embodiment illustrated in Fig. 4, instead of permitting thestrip here designated 9 to extend freely from one roller to the other,while passing through the secondary coagulation bath I23 in the tank I22and while passing through the water I28 in the tank I29, it will besupported on the endless band 46 with the surface of the strip H9exposed which formerly adhered to the face I 92 of the drum I03. When sosupported on the endless band 46, it will be noted that the rollers I40in the lower portion of the tank I22 will be chambered at I 4| so thatthe exposure of the face of the strip I19 here sought will not beinterrupted.

For convenience, the strip I9 7 Furthermore, in this embodiment, insteadof permitting strip H9 to extend freely from one roller to the otherwhile passing through the acid bath I35 in the tank I31, it will herepass directly from one roller to another, see the upper row of rollers41 and the lower row of rollers 48 staggered relative to one another andoverlapping one another effectively to support the strip H9 throughoutits passage through the tank I31. Here, too, the acid bath is constantlybeing renewed and being fed to the several inlet pipes 49 with dischargeopenings directed at the faces of the strip H9, as they pass from oneroller to the other. The tank I 31 is also provided with an outlet 50 topermit the bath fluid to pass therefrom so that the copper, if in excessof five per cent, may be removed therefrom and fresh acid supplied tothe predetermined concentration.

It is of course obvious that the baths 23 and 28 as well as the baths i23 and I28 may be renewed continuously as well as the other baths.

While it is desired not to be limited to the proportions, hereinafterset forth, it is claimed that the proportions here used in the processdis closed and machines used are new and particularly advantageous.

As an instance, excellent results have been achieved when the steps nowto be describedand proportions indicated are selected.

First, it is well to note that it is desirable to observe the chemicalproportions hereinafter set forth so that the coagulation may take placecorrectly and tension-free into the inside of the solution 19 in orderto facilitate faultlessly removing the finished strip 19 from the base 2when the strip has already so solidified that it is self-sustaining andthere will be no disadvantageous changes by the ensuing treatments intanks 22, 29, 31 and the like.

The solution 20 introduced through the nozzle I consists essentially ofan amount of cellulose corresponding to 5 to 8 per cent by weight of theentire solution, an amount of ammonia corresponding to 45 to 85 per centby weight of the cellulose content, an amount of copper corresponding to36 to 43 per cent by weight of the cellulose content, and an amount ofsodium hydroxide which should not exceed 44 per cent concentration ofthe cellulose.

The fluid in the trough 5 constituting the r coagulation bath, shouldconsist essentially of a watery solution of sodium hydroxide inproportion of 5 to 9.5 per cent by weight of the bath, of ammonia inproportion of 0.1 to 0.5 per cent by weight of the bath, and of copper,dissolved in the fluid, of 0.1 to 1.2 per cent by weight of the bath.

The easiest manner of adding the agents sup-' plementary to the sodiumhydroxide is by starting the process with a coagulation bath of sodiumhydroxide in the proportions heretofore recited and dissolving the otheragents by the coagulation of a smaller amount of the cellulose. Thecoagulation bath absorbs the ammonia and the copper of the cellulosesolution at once and the concentration of the proportions in this waywill be quickly standardized which has to be observed during theprocess.

The transformation of the cellulose solution 2i! into a solid,self-sustaining strip is done by dipping the pouring base 2 covered withthe layer l3 by rotating or other movement of the base 2 into thecoagulation bath in trough 5. The cellulose layer I9 is here coagulatedfrom one side while the other uncoagulated side adheres closely andunmovably to the base 2 .until the coagulation is completed.

The effect or rather the changes which take place in the layer l9 whilepassing through the trough 5 with the recited proportions of theingredients both in the solution and in the fluid constitute theimportant steps in the process for obtaining uniform and tension-freestrips. It has been found essential and advantageous that the ammoniawhich during the coagulation diffuses from the cellulose layer l5 intothe coagulation fluid in the trough 5 is immediately washed out.Therefore, it is better that the coagulation fluid passes in a streamalong the solution layer I9 throughout its entire extent and in anopposite direction to the movement of the pouring base 2. Only bymaintaining the coagulation bath in motion in this way can the ammoniacontent be watched so that a detrimental accumulation on the boundarysurface will be avoided.

The rate of flow of the fluid through the trough 5 will be determined bythe respective components or ingredients of the solution introducedthrough the nozzle l, the ingredients of the fluid in trough 5, thvelocity of the movement of the base 2, the thickness of the layer l9,and, finally the extent and width of the fluid passage formed by thetrough 5 and the base 2. Therefore, when the velocity of the flowisproper, it will be possible to maintain the total concentration of theammonia in the coagulation fluid below 0.8 per cent by weight, and therisk of a detrimental accumulation of ammonia on the boundary surface orin pockets will be avoided. With the maximum quantity of ammonia in thecoagulating solution, namely, 0.8 percent by weight, and the minimumamount of ammonia in the solution being coagulated, namely 2.25 percentby weight, the ammonia content of the former is approximately 35.55percent of the ammonia content of the latter.

Since during the process by continuous coagulation additional quantitiesof ammonia will steadily enter into the coagulation bath from thecellulose layer, the ammonia has to be continuously removed from thecoagulation bath so that the concentration of ammonia-will not exceed0.8 per cent by weight. This is accomplished as an instance when thefluid is removed from trough 5 through the discharge I8, the ammoniathereupon distilled off so that it will again be reduced to 0.1 to 0.5per cent by weight of the fluid and this fluid then cooled oil andreturned to the trough 5 through the inlet H.

The accumulation of copper in the fluid content of the trough 5 canordinarily be ignored if care is exercised occasionally to remove thecopper content when it exceeds 0.1 to 1.2 per cent by weight of thefluid.

The next step will be the washing of the strip [9 in order to rinse offthe adhering part of the coagulation fluid as well as to dilute andpartly remove the coagulation fluid seeped into the strip IS.

The rinsing or soaking of the strip l9 after it has been removed fromthe base 2, eventually, as set forth passes a second coagulation bathwhen it will be subjected to a bath of either water or a weak solutionof sodium hydroxide. The rising may only be continued until theconstituents of the strip I9 have been reduced to 20 parts by weight ofcopper, 3 parts by weight of ammonia and 22 parts by weight of sodiumhydroxide, referring to a parts by weight of cellulose. If the rinsingprocess should continue after this reddctionrhas:been reachedf the strip'1 9 is in "dam-2. ger of becoming too delicate and deformed ;re.-.sultingzin' destructive "internal tensions,- irregularitiesmtriationsand the like.

The .:washed:film;thereupon: is passed into. an acid :bath'infwhi'ch'the. cellulose will be entirely regenerated and the copperwill be removed from" thestrip/ It has beenfound advantageous to user;as-sulphuriclacid7bath5of more than 2 .and less thamfasipen'centbyweight-iat temperatures of' morethanr'75 and-Jess than ;125.-degreesFahren-. halt:-

Iniithisl 'bath-thexshrinkin'g :of "the strip takes place;.-initially.rHereby a satisfactorily uniform treatment lot the :strip .11 9 Withoutinducing any tensions;shri11kages or the like in the same canbe:obtained::- the preliminary coagulation and washing-:has :beendone ina "careful manner,-and the; concentration, temperature and the. likehave been followed closelygas mentioned.

Preferably lalsovthesbath 3671s. being continualiyia'eneweckithebathfluidsentering the tank1=31i througlmthe. inlet" .44 z and leaving 1the tank; 3'!v throughthe outlet. 45 so that the bath :fluid flows--past-etheistripz I955 In-order .to :have the acidso lutionsspread'uniformlyronto the :strip; the :inletMeismonnected.tozanrextendeditubular spray 44 1 an'd-gbranchwayszThescopper."dissolved in the acidr'solutioniwilibe removed from thefluid which is dischangedthroughf'outlet 45;.andthe fluid will Iagainrberreplenished withifresh 'a cid and reheatedrto the desiredtemperature. The copper con-- tent ofxtheacid 'SOllltfOIl'iShOll'ld notexceed ,5 per: centsby weight ofthe bath-fluid? Aft'enzthe strip l 9 hasbeenrcompletely freed of copper; it is now.passed through-several bathsof 5 clean; clear: :water and impregnated; .with softeneersaandtplasticizers and *dried;

Strips made according to the present process" and byth'e present machineare characterized by not having been stretched; extended 'or shrunk'tor-any :appreciable extent during the process of coagulation" andwashingrresulting in a uniform physicali'tstructure throughout, freefrom striaflorist-streaks and irregularities ofany kind;

on account of "the 'uniformtreatment on the 1 base in' the'firststage-of "the process when the transformation from the liquid into thesolidified state-take -place,'the process is especially'suited for-themanufacture of thin strips'and has been develdpedespecialiy'for thispurpose.

Irraccordance withthe present process; itis' possible tomanufacturesheet like strips not only having a weight of less than'0f35ounce=per thousand-square inches; but ialsorhavinga' weight oflessw-tlianfozwpunce and less than 0.1Dounce per thousand square"inches,all characterized by being: without striations, streaks andirregularities" of any kind. Strips of the weightjustindicated 1h'avev-a:ithie'lmess -of- "the order which .is :herein referred tdasithin.

It isipbvious that various-chan es and modifi cations "may-be made tothe details of construe-:1 tion without departing from the generalspirit of the inventionras set forthiin the appended claims. 65

I claim:

1: A flexible' andwer-y strong cellulose hydrate strip'rcapable-of.beingcrushed and crumpled and? characterized: :by r a uniform physicalstructure having a a practically equal tension and shrinkage 70characteristic throughout; free 1' frominternal; stressesxsaid stripbeing "produced by directly? supportingan'd then spreading :on adrysupport= in-g surface a-copper oxide ammonia cellulose so:-."- lutibn'andieflectively coagulating ;saidispreadxsoe;- 7

8% lution -by-:penetrating:the so-spread ;,solutiorr:.via. the exposedisurface thereof withra :coagulatinge; medium while saidsolutionisincontact withsaid supporting surface until the coagulating .mediumz:

:. finally'penetrates torthe supporting.surfacento;

; being produced 1' by directly supporting rand then:

spreading, on:a dry supporting "surface a copperoxide ammonia cellulosesolution. and ,efi'ectlvelyz coagulating saidispread solutionhypenetrating; the so spread solution-via the. exposed "surface thereofwith .a :coagulati-ng medium: while. .said 1 solution is inv contactwith said supporting iSllli' I face until the. coagulating -mediumfinally-penetratesto the, supporting surface'to form'a-thln': layenand"thenr regenerating the -thin-:layerso formed by passingthe same throughan acid bath-.1-

and finally Washing the same.

3. A flexible and very strong cellulose hydrate strip capable of beingcrushed and crumpled ands characterized by"a-uniform physical structurehaving a practically equal tension and shrinkage characteristicthroughout; free from internal stresses; and having a weight perthousand 5; squareinches-of less than 0.'10-ounce,--=.said:strip-1 beingproduced :by directly supporting and-then. spreading'ona dry supportingsurface acopper oxide ammonia cellulose solution. and eil'ectivelycoagulating said spread solution'by penetrating the so spreadsolution'via the exposed surface 2 thereof with a coagulating medium while-saidS0-.'- lution is in contact with said supporting surface untilthecoagulating mediumfinallypenetrates to "the supporting "surface to forma'thinlayer;- and then regenerating the thin -layer so 'formed': bypassing the same through an: acid bath and:

- finally washing the same.

same into substantiall'y'solid strip whilesaid so lution is in contactwith said supportingsurfacew until the coagulating medium finallypenetrates; to the 'supportingsurface; removing the thus formed solidstrip "fromrthe supporting surf ace: and removingrthe coagulatingmediumrwhichthasaz penetrated to :the supporting "surface .fIOHTSfiidsupporting surface tQ prepare-it: f orwa fresh supe ply of copperpxide',ammonia :cel-lulosesolutionr 5. A continuous -processof manufacturing"0815 lulose hydrate strips comprising directly supply: ing'toandisupportingon amovable dry-supports ing surface a copper :oxideammonia'cellulose so: lution in which the ammonia content isapproxh Imately 45 .to :85 fper cent of the cellulose,=spread ing the: solutionso supported and while:being-: moved with-the :supporting surface :into'azithin layer, penetrating: the. solution :with a-coagulating 'tmediumefiectively to coagulate the solution as:a" thin layer to-convertithesamezinto-a sub'e f stantiallyisolimstriniwhile said solutioniszimconatact with said supporting surface until the coagulating medium finallypenetrates to the supporting surface, removing the thus formed solidstrip from the supporting surface, and removing the coagulating mediumwhich has penetrated to the supporting surface from said supportingsurface to prepare it for a fresh supply of copper oxide ammoniacellulose solution.

6. A continuous process of manufacturing cellulose hydrate stripscomprising directly supplying to and supporting on a movable drysupporting surface a copper oxide ammonia cellulose solution, spreadingthe solution so supported and while being moved with the supportingsurface into a thin layer, advancing the solution as a thin layerthrough a coagulating medium containing approximately to 9.5 per centsodium hydroxide, 0.1 to 0.5 per cent ammonia and 0.1 to 1.2 per centcopper and penetrating the solution with such coagulating mediumeffectively to coagulate the solution as a thin layer to convert thesame into a substantially solid strip while said solution is in contactwith said supporting sur face until the coagulating medium finallypenetrates to the supporting surface, removing the thus formed solidstrip from the supporting surface, and removing the coagulating mediumwhich has penetrated to the supporting surface from said supportingsurface to prepare it for a fresh supply of copper oxide ammoniacellulose solution.

7. A continuous process of manufacturing cellulose hydrate stripsconsisting in directly supplying to and supporting on a movable drysupporting surface a copper oxide ammonia cellulose solution, spreadingthe solution so supported and while being moved with the supportingsurface into a thin layer, penetrating the solution with a coagulatingmedium effectively to coagulate the solution as a thin layer to convertthe same into a substantially solid strip while said solution is incontact with said supporting surface until the coagulating mediumfinally penetrates to the supporting surface, removing the thus formedsolid strip from the supporting surface, and removing the coagulatingmedium which has penetrated to the supporting surface from saidsupporting surface to prepare it for a fresh supply of copper oxideammonia cellulose solution, continuously renewing the coagulating mediumto maintain the ammonia content thereof below 0.8 per centfand finallyregenerating and washing the solid strip so formed.

8. A continuous process of manufacturing cellulose hydrate stripsconsisting in directly supplying to and supporting on a movable drysupporting surface a copper oxide ammonia cellulose solution, spreadingthe solution so supported and while being moved with the supportingsurface into a thin layer, penetrating the solution with a coagulatingmedium effectively to coagulate the solution as a thin layer to convertthe same into a substantially solid strip while said solution is incontact with said supporting surface until the coagulating mediumfinally penetrates to the supporting surface, removing the thus formedsolid strip from the supporting surface, removing the coagulating mediumwhich has penetrated to the supporting surface from said supportingsurface to prepare it for a fresh supply of copper oxide ammoniacellulose solution, successively passing the strip so formed throughfurther treatment baths until the strip so formed consists of about 100parts by weight of cellulose, 20 parts by weight 10 of copper, 3 partsby weight of ammonia, and 22 parts by weight of sodium hydroxide, andfinally regenerating, washing, cleaning, impregnating with softeners anddrying the strip so formed.

9. A thin flexible and very strong cellulose hydrate strip capable ofbein crushed and crumpled and characterized by a uniform physicalstructure having practically equal tension and shrinkage characteristicsthroughout and free from internal stresses, said strip being produced byscraping the surface of a support to substantially dry the same, thensupplying to the support a copper oxide ammonia solution which adheresto the support, spreading the solution on the support, and effectivelycoagulating said spread solution by progressively penetrating the sospread solution via the exposed surface thereof with a coagulatingmedium while said solution adheres closely on its unexposed side to saidsupporting base until the coagulating medium finally penetrates throughsaid solution to the supporting base to form a thin layer, then removingsaid coagulated layer from said supporting base, and finallyregenerating and washing the thin layer so formed.

10. A flexible and very strong cellulose hydrate strip capable of beingcrushed and crumpled and characterized by a uniform physical structurehaving practically equal tension and shrinkage characteristicsthroughout and free from internal stresses and having a Weight perthousand square inches of less than 0.35 ounce, said strip beingproduced by scraping the surface of a support to substantially dry thesame, then supplying to the support a copper oxide ammonia solutionwhich adheres to the support, spreading the solution on the support, toa thinness corresponding to the said weight per unit area in the finalstrip and effectively coagulating said spread solution by penetratingthe so spread solution via the exposed side thereof with an alkalinecoagulating medium while the inner side of said solution is in contactwith and adheres closely to the supporting base until the coagulatingmedium finally penetrates through said solution to the supporting baseto form a thin layer, and then regenerating the thin layer so formed bypassing the same through an acid bath and finally washing the same.

11. A continuous process of manufacturing cellulose hydrate stripscomprising directly supplying to and supporting on a movable drysupporting base a copper oxide ammonia cellulose solution, spreading thesolution so supported and while being moved with the supporting baseinto a thin layer of a thickness corresponding to a weight per thousandsquare inches of less than 0.35 ounce in the final strip, treating thesolution with an alkaline coagulating medium effectively to coagulatethe solution as a thin layer by progressive penetration of thecoagulating medium through said solution to solidify said solution intoa se1f-sustaining strip while its inner side is in contact with andadheres closely to said supporting base, and while said solution ismoved with said supporting base through the coagulating medium for theperiod of penetration of the coagulating medium through the solution andfinal- 13' to the supporting base, then removing the thus solidifiedstrip from the supporting base, and removing from said supporting baseany material adhering thereto so as to prepare said base for a freshsupply of a copper oxide ammonia cellulose solution.

12. A continuous process of manufacturing cellulose hydrate stripscomprising directly supplying to and supporting on a movable drysupporting base a. copper oxide ammonia cellulose solution, a

layer ofa thickness corresponding to a weight per thousand square inchesof less than 0.35 ounce in the final strip, treating the solution withan ammoniated alkaline coagulating medium, regulating the ammoniacontent of the coagulatingmedium during said treatment to maintain itwithin the range of 0.1 to 0.8% to coagulate the solutionasa thinlayer-by progressive penetration of the coagulatingmediurn through saidsolution to solidify said solution into a self -sustaining strip whileits inner side is in contact with and adheres closely to said supportingbase, and.while said solution: is moved with said supporting basethroughthe coagulating medium for the period of: penetration of thecoagulating-medium through the solution finally to the supporting base,then removing the, thuslsolidified strip from, the supporting base, andremoving from said supporting base any-material adhering thereto so asto prepare-saidbase for a fresh supply of acopper ox:- ide ammonia.cellulose solution.

L3,; Aicontinuous process of manufacturing cellulosehydrate stripscomprising directly supplying toy and supporting on a movable drysupport,- ne: base a; cop er oxide ammonia cellulose solutiom inwhichthe; ammonia content is approxi mately:45 V to; 85 percent; of thecellulose, spreading: the solution so supported and while beingmovedwith;the;support-i,ng base into a thin layer of: a;thickness-corresponding to'a Weight per; thousand-v square; inches. oflessthan 0.35;ounce in the final strip; treating: the solution with analkalinecoagulating; medium containing 0.1v to 0.5 percent ammonia by:weight effectively to coagulate: the solution as. a thin layericy-progressive penetrationtotthe-coagulating medium throughsaid'solutionytosolidify-said: solution into a self-sustainingstripwhile its inner-side is in" contact withv support; then; pull ng the thf rmed; film-mom p rt. p ea i g t e s lu ion n h upp rt ndsimultaneouslymeterings the same; to regulate,

the thickness; and width, eithe solution layer ad he ne, to he u port.o. that; when cme la d, v regenerated, and dried theresulting sheet willhave; a. weight; of not. more than 0.35 ounce per thousand squareinches, said, solution adhering to the-support with a; tenacitysufficient: to resist Widthwise shrinkageiorces; incident to coagulation, then contacting; the exposedsideof the adhered solution with analkali, coagulant. until, the coagulant'penetrates throughthe-solutionto thes u-rface of the support thereby converting thesolution by, coagulation: into a self-sustaining layer, theeohesiye-fonces of the film layer sov form/ed, now emzeeding the,adhesive, forces be.-v tweenthe formed film layer and the support re.

the support, and regenerating the film.

Intthecontinuous manufacture of thincele lulose hydrate sheets, theprocess comprising scraping thers lrface; of alsupport tov substantiallylate the thickness and width of the solution, layer dry the sanie thensupplyingacoppel; oxide am.-

moniacellulose solution which v adheres to the.

support, spreading the, solution ontthe, support and simultaneously,metering the same to: regu:

adheringitol the support so, that. whenv coagulated,

reg nerated, and. dried th resultin sheet will.

have a weight of not more than 0.35 ounce per usa square. in h s aisl'.lu i n. a her n to. the, upport witha ena ity suffici n o i t?widthwise; shrinkage, forces incident to coagulahered solutign with anammoniated alkali co. aeu ant'l until the. o gulan p n rates thro h. thesolution to thesurfaoe of the support thereby convertingthe solution bycoagulation into a self sustaining layer, the ammonia content of saidcoagulant being in the proportion of not. more 7 than 35.55 percentofthe ammonia content ofthe, solution being;coagulat'ed; the cohesiveforces of the film layer so formed now exceeding the adihesiye forcesbetween the formed film layer and" the support restraining movement of.the film relatively to the, support,thenpulling the thusformed; film,from, the support and regenerating the film.

CZAPEK;

